Laminated wooden plate



Apri] l1, 1,939. G. KHR

LAMINATED WOODEN PLATE Filed oct. 9, 193s Patented Apr. 1.1,- 1939v l'UNITED STATES Pari-:NT OFFICE Application October 9, 1936, .Serial No.' 104,897 In Sweden October 19, 1935 Laminated plates of a similar kind are known lo in which the core consistsof a single compact block of wood which, in order toavoid warping, is cut in on opposite sides, the cuts or incisions extending perpendicularly to the direction of the libres. Notwithstandingthis such a plate is liable l to swelling in a direction along the plane of the plate transversely of the libres. If such plates are made of hard wood, for instance oak, which is desirable for obtaining a high sound Vinsulating capacity, the plate, in spite' of the incisions, will possess a considerable residual elasticity which may cause warping oi the plate.

According to the present invention I compose the core of a plurality of parallelly disposed rods or laths, in which the fibres extend substantially in parallel with the surface 'of the plate and longitudinally of the rods, and I sever or cut the fibres by making incisions alternately from oppo- 'site sides of the rods, such incisions extending through part of the rods only. Due to the interstices between the rods tensioning of the plate in a direction perpendicular to the direction of the ilbres is thereby prevented. When composing the core of a plurality of rods'it becomes possible at'the same time to remove more completely the spring effect oi the wood bycutting the bres through by means of incisions extending inwardly from more than two and preferably from all four sides. This latter arrangement is oi particular importance with hard woods, the spring effect in which cannot be removed entirely by the arrangement of incisions extending from two opposite sides only.

The invention 'will now be described more inl detail, having reference to the drawing anixed in this specification and forming part thereof which shows in a diagrammatic manner by way oi example an embodiment of my invention.

In the drawing Figure 1 is a section of part of -the plate -o'n the 65 Figure 5 illustrates a detailon a larger scale.

lplywood, masonite or the like.

Referring to the .drawing I are the rods forming the core oi the plate, which are positioned in parallel with each other between parallel 'planes and are spaced somewhat, interstices 2 being formed between them. The ends of the rods are formed with tongues 3' which t into corresponding grooves in transversely extending edge laths 4 which together withside'laths 5 iorm a `reinforcing frame, which holds the parts together. If such a frame 4is provided it is not 10 necessary to fit the ends oi the rods into the frame by means of tongues or the like, but obviously the mechanical strength oi the plate is inl creased thereby. Glued onto opposite sides of the core are surfacing sheets 6 of cross-veneer, 15

The rods i, which have a rectangular cross-section, are formed withincisions 1 oi considerable depth, which extend t alternately from the four sides through the greater part of the thickness of the rods so that 20 each rod still forms a coherent unit. In the example shown in Figure 2 the uppermost incisions 1, thus extend from the top sides of the rods, the other incisions starting from'the right hand side, from below, and from the left hand side of each 25 rod, respectively. The side laths 5 are formed. with incisions B starting from the inner side only.

Owing to the provision of the 'incisions 'l the` fibres are cut through at a plurality of points,

thereby losing the capacity of setting up internal 30 stresses in the wood through contraction or expansion in the longitudinal direction.. The incisions may also extend from two sides of the rods only, depending upon the kind of wood used. A

more even and complete equalizing of the internal 36- strains .is obtained. however, if the incisions, as

,in the embodiment shown in the drawing, ex-

tend alternately from all four sides.`

The incisions 'I in therods i, as well as the incisions 9 in the side lathsv 5 are filled with a filling 40 material, for instance a binder I0 (Fig. 5). I prefer using glue or some other suitable substance capable of preventing the rods from being weakened by the incisions. Actually the rods,

lafter complete solidication of` the glue, possess 45 considerable strength at the points of incision. I prefer filling the binder into the incisions immediately before the core is tted'together and the surfacing sheets 6 placed in position, so that the binder will set, while the plate is subjected in the usual manner to heavy pressure in a hydraulic press or the like, and simultaneously with the' pressing-on -of the surfacing sheets 6.

In'Y order' to prevent that, when pressing the plate together, the sheets i are forced into the `gaps 2 between. the rods, whereby' the suriace of the platel wouldbecome uneven, the rods l can be arranged in closey juxtaposition, as shown in Figure 4, the adjoining faces of the rodsbeing hollowed out, so that the rods will bear against 'each other only .along vcomparatively narrow vedges 8, being partly separated by lonaitudinal' cavities i2.

No reinforcing frame need surround the core, however in that case I prefer to cover the lateral edges of the plate it they should be formed with cavities I2, with laths or strips I6 oi' cross-veneer or vthe like. 4 l

In order to increase the sound insulating capacity oi' the plate I may lill thegaps 2 with an elastic sound insulating material, such as paper board in the form oi.' strips or the lige.

Plates according to this invention can be used in the construction of doors, table tops, the side 20 walls of cupboards or the like, or as wall covering material.

I wish it to be understood that I do not desire to be limited to the exact details of construction" shown and described for obvious modication's will occur to. a person skilled in the art.

I claim:

1. A laminated wooden plate comprising in` combination, a plurality of rods arranged in parallel juxtaposition and a surfacing sheet covering the row of rods on either side, the ilbres in said rows extending substantially in the longitudinal direction of the rods, the rods being formed'with incisions extending alternately from all tour sides oi' the rods to a depth such a's to effectively sever the bres at spaced intervals. y

2. 'I'he laminated plate of claim 1, in which the rods are formed with a rectangular cross section.

3. The plate of claim l, in Lwhich a binder is arranged in the incisions.

operar Riina; "2o 

